Many high-purity operations require clean, pure processing environments and containers. Polymers used in these applications must be extremely chemical resistant and capable of being easily sterilized. The high-purity polymers find use in applications including bags or other containers for high purity fluids, biological and biomedical media and high purity chemicals and reagents.
For polymer bags for use as disposable liners in biological/biochemical reactors, current bags have limited chemical resistance and are generally assembled and sterilized offsite by gamma radiation. Current technologies include a multi-layer structure and mono layer films with contact layers made of ethylene vinyl acetate (EVA) and linear low density polyethylene (LLDPE); 100 percent polychlorotrifluoroethylene (PCTFE) films or PCTFE films co-extruded with a heat sealable polyolefin layer. These films may include a nylon layer for strength and/or an ethylene vinyl alcohol (EVOH) as a barrier layer.
One problem is that current bags cannot be sterilized in a steam autoclave, as they will melt together and become useless. They are also not easily heat-sealable, or require an extra step to provide heat-sealability, such as the added coextrusion of a polyolefin layer.
Fluoropolymers, and especially polyvinylidene fluoride (PVDF), are known to be highly chemical resistant. Fluoropolymers can be cast into films, including multi-layer PVDF/functionalized polymethyl methacrylate film described in U.S. patent application Ser. No. 10/678,795. In this film, there is not a pure layer of PVDF, but rather a blend of PVDF and another polymer.
There is a need for a polymer material that can provide a high-purity contact surface and can be steam sterilized or gamma ray sterilized, and is heat sealable.
Surprisingly it has now been found that films having at least one melt processable fluoropolymer layer, provide a high-purity material that can be steam sterilized and gamma sterilized.